I would like to change the default grid-line color (default color is a light grey) to something custom and I can't seem to locate the property to do this. My chart type attribute is set to ScatterChart. I'm using version 7.3 of the Infragistics2.Win.UltraWinChart library.
You can try using:
this.ultraChart1.Axis.Y.MajorGridLines.Color = Color.Black;